Reduction of oxide ores



July 29,- 1930. w. E. TRENT 1,771,972

REDUCTION OF OXIDE ORES Filed May 8, 1929 '2 Sheets-Sheet anbentoz W0//er. 7220/ July 29, 1930. w. E. TRENT REDUCTION OF OXIDE ORES File May 192 2 Sheets-Sheet 2 OQOOOGOO. Q@-

OOQO OCC Qw o ooooooooooooooooooooooo 000 Sum/Mex Patented July 29, 1930 MUNITED STATES PATENT OFFICE WALTER E. TRENT, OF NEW YORK, N. Y., ASSIGNOR TO TRENT PEOCESS CORPORATION,

OF NEW YORK, N. Y., A CORPORATION OF DELAWARE REDUCTION OF OXIDE ORES Application filed Kay 8, 1929. Serial Ho. 881,498.

This invention relates to the reduction of oxide ores, and more particularly to a continuous process in which the reduction of the ore proceeds simultaneously with the crack.-

ing and gas'ification of liquid hydrocarbons, and in which the heat contained in the hot freshly reduced metal is utilized in promoting the cracking and gasification reactions. This application is in part a continuation of my application Serial No. 285,953, filed June 16, 1928, in which I have disclosed and claimed broadly the idea of utilizing the heat contained in hot freshly reduced metal such as iron in sponge form, to eifect cracking of liquid hydrocarbons and at the same time to protect the metal particles from re-oxidation y forming a coating of hydrocarbons thereon. The process in its broader aspects also involves the recovery for use of the hydrocarbon vapors and gases derived through the cracking reaction, the condensable fractions being condensed and subjected to suitable refining operations and the fixed gases being either utilized in effecting reduction of fresh uantities of ore or collected and utilized as fuel for any desired purpose. a

It is desirable around steel plants to have available a large supply of fuel gases. I have found that by operating the process of the parent application above mentioned under suitably controlled conditions the cracking of the liquid hydrocarbons may be carried to such an extent as to produce large amounts of gases of high fuel value and suitable for use for various industrial purposes.

The process also affords-a simple method of producing fuel gases of varying composition depending upon the. use to which they are to be put. The process will be described more in detail in connection with the accompanying drawing illustrating onef'form of apparatus which may be employed in carrying out the invention.

"Fig. 1 is a part vertical section and part side elevation of the apparatus; and

Fig. 2 is a part vertical section and end elevation taken on the line 22 of Fig. 1.

The apparatus, designated generally at'10 and similar in general respects to that de- 50 scribed inthe earlier application above mentioned, comprises a vertical reducing chamber 12, formed by side walls 14 and end walls 16. Extending across the chamber 12 are a plurality of tubes 18 which open at their ends into spaces 20 between the side walls 14 and outer walls 22 for the reception of the products of combustion from gas burners 24 disposed near the lower end of the retort.

The spaces 20 are arranged in checkered. fashion, as shown in Figs. 1 and 2. Details of this arrangement, desi ned particularly to secure most eficient gas ow, are immaterial to the present invention.

It can be seen, however, that the gases of combustion from burners 24 will traverse the tubes'18, heating the same and providing indirect heat for the contents of the. chamber. 12. Suitable means are provided, including headers 26, blowers 28, conduits 30, and bypasses 32, for recirculating at will a portion of the partially cooled-gases, or to by-pass the gases or a portion of them, thus permitting close control of the temperature of the chamber 12 and making it possible to increase or decrease the amount of heat suppliedto the contents of any portion thereof at any stage 0f the operation. Waste gases are led from headers 26 to an external flue, not shown.

Extending across chamber 12, horizontally and at right angles to tubes 18, is a plurality of groups of eduction tubes, 34, 36,38 and 40. The number of groups ofsuch tubes is not critical, but there may well be at least two; the upper connected to'a blower 42 for the purpose of removing air accidentally or unavoidably introduced with the charge to be described later. The lower group or. groups of eduction tubes may feed into a conduit 44, which may, if desired, connect with a condenser shown generally at 46, for a purpose to be later disclosed. These tubes have open- ,ings 48 through which gases and vapors may pass from the chamber 12. A fee hopper 50 is provided from which discharge to the chamber 12 is regulated by the slide valve 52.

At the lower part of the apparatus is an oil reservoir 54. The reservoir extends from beneath the. lower end of the chamber 12 to a point outsidethe'walls 22,;being com pletely enclosed partly by the walls of the chamber 12 and partly by a gas collecting chamber 56. Oil is fed into this reservoir through a pipe 58 from any convenient outside source as noted. In the floor of this reservoir is a series'of parallel screw conveyors 60, all -pitched;tof.feed centrally-into one or more cross troughs 62. A conveyor or conveyors 64 are disposed in the cross troughs 62 andadapted when rotated to feed into a sump 66. All of the conveyors 60 and 64 may be operated from a motor 68.

In order to withdraw gas formed by contact of the hot freshly reduced metal with the oil bath or the vapors therefrom, a suction fan 70 may be provided in the eduction pipe 72 leading-either directly or through a scrubber to asuitable collectingtank, not shown. In order that gases generated in the lower portion of the chamber 12 may be readily Withdrawn through the pipe 72 it is preferable to maintain the oil level in the oil reservoir such that a free passage 74 is provided from the chamber 12 to the gas collecting chamber 56, as shown in Fig. 1.

The reduced metal discharged into the sump 66 may bewithdrawn therefrom in admixture with oil and forced by the pump 74 through the pipe 76 to a settling tank 78 in which the metal particles may be permitted to settle to the bottom while the oil is withdrawn either continuously or intermittently through the line 80 and the pump 82 and returned to the reservoir.

As set forth in the earlier application above mentioned, in carrying on t e reducing operation the ore may be introduced to the retort chamber 12 either alone or in admixture with a suitable solid carbonaceous material. According to one modification of the process, an iron oxide ore and a finely divided bituminous coal, either of a coking or non-coking variety, which have been reduced to finely divided form and intimately mixed, are introduced to the hopper 50 and gradually fed by gravity downwardly through the chamber 12, the feed valve 52 being open during operation. The gas burners 24 are started and the tubes 18 so heated that the temperature within the chamber 12 is high enough to reduce the iron oxide in the presence of the carbon of the coal. The charge noW feeds slowly down through the chamber 12, becoming progressively hotter as it descends. It is preferable to so control the rate of feed and the temperatures that the iron oxide will be completely reduced to the metallic state by the time it has reached the lowermost horizontal row of heating tubes 18.

The hot metallic particles then feed into the oil bath, the immediate effect of this being to quench the metal and transfer a large part of its heat to the oil. As a result, the oil will be partially volatilized and cracked. The proportion of fixed gases formed by cracking the oil or other hydrocarbon liquid the operation with a view to producing large volumes of gas, the rate of circulation of the oil in the oil reservoir 54 should be retarded so as to maintain a high temperature in the bath by reason of the absorption of the sensible heat of the reduced metal.

Instead of Withdrawing the gases that are formed to a scrubber or gas holder through the pipe 72, it may be desirable to pass them through the charge in the chamber 12 in countercurrent relation thereto. In this way the heating of the charge may be promoted and at the same time the gases and. vapors evolved from the oil bath may be brought for a long period into contact with reduced or partially reduced constituents of the charge under conditions promoting further cracking and gas formation. When the process is so operated the gases formed may be led in admixture with volatilized constituents of the oil or the carbonaceous material of the charge to the condenser 46 or through a suitable bypass line to a gas scrubbing unit or gas holder. In Fi 2 there are shown 'by-pass lines 84 and 86 connected to the conduit 44 for optionally withdrawing all or part of the gases and volatiles derived during the reducing and gasification reactions from the retort chamber without passing same through the condenser 46. Valves 88 and 90 are provided in the lines 84 and 86, respectively, and similar lines 92 and 94 are provided in the-conduit 44 respectively intermediate the lines 84 and 86 and the condenser 46.

When using a bituminous coal as the solid reducing agent mixed with the ore, it will be understood that distillation of the volatilizable constituentsof the coal takes place in the upper portions pf the chamber 12, and that generally it will be desired to pass these constituents to the condenser to recover the condensa-ble fractions. On the other hand, when using coke or a low volatile coal, the apparatus above described affords a convenient and simple means for recovering fixed gases produccd in the reduction of the ore separately neous reduction of an oxide ore and I tion of l1qu1d hydrocarbons COIIIPI'lSlIlg conbath maintained inthe reservoir 54. When the process is beingso operated'it is desirable to permit all of the gases and vapors evolved from the oil'bath to pass upwardly through the char e and not'to withdraw part through the line 2. v

The. oil bath is maintained in the reservoir 54: by continuously or intermittently adding thereto oil that has been removed with the reduced metal articles to the separating tank 78 together with sufficient fresh oil to compensate for the losses due to gasification and vaporization of constituents thereof in the gasification zone.

The process is of a quite flexible nature in that the vapors and gases obtained from the oil may be of a controlled quality and quantity. Should it be undesirable to produce large quantities of fixed gases, this objection can be obviated by regulating the amount of oil flowing through the well 54. If a large amount of oil is continuously admitted to this well its temperature raised by heat ab sorbed from the hot metal will be less than the temperature attained if only a small quantity of oil is introduced to the well. Of course, the higher the temperature the greater will be the extent of cracking or conversion and the amount of fixed gases produced. The flow of oil to and through the well is subject to such control that even distillation without substantial cracking can be effected in this process.

The quantity of oil admitted to the well, however, should be sufiicient on all occasions to carry in suspension from the retort the metallized particles in order to revent these particles from accumulating in t e well and agglomerating or fusing. This control of the oil in addition to controllin the products obtainedtherefrom, serves the further purpose of enabling the metallized particles to be carried from the heater in a more or less plastic mass or in free oil suspension, the oil serving as a vehicle to remove or discharge the treated metallized particles from the heater.

I claim:

1. A continuous process for the simultatinuously feeding an ore-carbon charge by gravity through an indirectl heated reduction zone, continuousl disc arging the reduced metal as forme into a bath ofliquid hydrocarbons to volatilize and gasify constituents thereof, continuously adding liquid hydrocarbons to said bath at such a rate as to insure a high degree of volatilization and gasification of said constituents and to convert a substantial portion of the oil into gas, and withdrawing and collecting said volatiles and gases as formed. 7 I

2. A continuous process for the simultaneous reduction of an oxide ore and gasification of liquid hydrocarbonscomprising continuously feeding an ore-carbon charge by gravity through an indirectly heated reduction zone, continuously discharging the reduced metal as formed into a bath of liquid hydrocarbons to volatilize and gasify constituents thereof, continuously adding liquid hydrocarbons to said bath at such a rate as to insure a high degree of Volatilization and gasification of said constituents and to convert a substantial portion of the oil into gas, and separately withdrawing and collecting the gases envolved in the reduction zone and the volatiles and gases produced in the hydrocarbon gasification zone.

gasification of said constituents and to convert a substantial portion of the oil into gas,

separately withdrawing and collecting the gases evolved in the reduction zone and the volatiles and gases produced in the hydrocarbon gasification zone, and removing the reduced metal in admixture with heavy residual hydrocarbons.

4. A continuous process for the simultaneous reduction of an oxide ore and gasification of liquid hydrocarbons comprising continuously feeding an ore-carbon charge by gravity through an indirectly heated reduction zone, continuously discharging the reduced metal as formed into an oil bath to volatilize and gasify constituents thereof, and so correlating the rate of feed of oil to said bath with the rate of feed of freshly reduced metal there-. to that a temperature is maintained therein and in the reduced metal being led thereto insuring a high degree of gasification of constituents of said bath and vapors evolved therefrom, and withdrawing and collecting said gases.

5. A continuous process for the simultaneous reduction of an oxide ore and gasification of liquid hydrocarbons comprising continuously feeding an ore-carbon charge by gravity through an indirectly heated reduction zone, continuously discharging-the reduced metal as formed into an oil bath to volatilize and gasify constituents thereof, and so correlating the rate of feed of oil to said bath with the rate of feed of freshly reduced metal thereto that a temperature is maintained therein and in the reduced metal being led thereto insuring a high degree of gasification of constituents of said bath and vapors evolved therefrom, and separating condensable constituents therefrom.

. 6. A process comprising heating a mixture of an oxide ore. and carbonaceous material to reduce the ore, contacting the freshly reduced metal While hot with a hydrocarbon oil under conditions suitable to convert a substantial portion of the oil into gas, and removing and collecting the gasesso formed. 7. A process comprising heating a mixture of an oxide ore and carbonaceous material to reduce the ore, immersing the freshly re duced metal as formed and before it has cooled substantially in abath of liquid hydrocarbons under conditions suitable to convert a substantialportion of the liquid into gas and subsequently recovering the resultant gases.

8. A process comprising heating a mixture of iron ore and carbonaceous material to reduce the ore, immersing the freshl reduced metal in a body of oil under condltions suitable for converting a substantial ortion of the oil into as, thereby volatilizing, cracking and gasiiying constituents of said oil, passin the vapors and gases so formed through a ody of partly reduced metal, ore and carbon, further to crack said oil vapors and gases, and subsequently separating the gases so produced from the condensable fractions of said vapors.

9. A process comprising indirectly heating an oxide ore under reducing conditions to effect reduction thereof, immersing the freshly reduced metal in a body of oil, to quench the metal, transfer its heat to the oil and protect the reduced metal from reoxidation, controlling the rate of introduction of reduced metal to said oil body so as to promote volatilzaton and to convert a substantial portion of the oil into gas, further cracking resultant volatiles and recovering the gases so formed.

1 0. The process of producing gases from liquid hydrocarbons which comprises maintainin gasifymg zone, continuously adding finely ivided, freshly reduced hot metal to said body in said zone to promote cracking and gasification of constituent hydrocarbons, withdrawing gasified constituents from said zone as formed, continuosly removing'the mixture of residual hydrocarbons and reduced metal, separatin hydrocarbon constituents therefrom an returning them to the said zone, and maintaining the body of hydrocarbons in said zone at a suitable temperature for effecting the desired asification by addin controlled amounts of resh liquid hydrocar ons.

11. The process which comprises heating a mixture of an oxide ore and carbonaceous material to reduce the ore, contacting the reduced metal while hot with a hydrocarbon (.3 liquid to gasify a substantial portion therea body of liquid hydrocarbons in 8.

of, collectin resultant gases, and separating said reduce metal from the residual hydrocarbon liquid.

12. The process which comprises indirectly heating an oxide ore in the presence of a reducing agent and at a reducing temperature until reduction takes place, immersmg the reduced metal while hot in a hydrocarbon liquid to vaporize the constituents thereof and to gasify a substantial portion of the liquid, subjecting resultant vapors and gases to cracking by contact with freshly reduced hot metal, and withdrawing and collecting the products of the cracking treatment.

In testimony whereof I aflix my signature.

ture.

' WALTER E. TRENT. 

